There are inherent problems in trying to align a reverse active etch photomask to the already patterned active shallow trench isolation (STI). Because of small variations and errors in the lithographic process, there is a built-in overlap. In addition to the lithographic margin, the typical high density plasma (HDP) oxide fill at this process step is sloped due to the nature of the HDP oxide process. This slope forces a certain amount of overlap to prevent printing the photo-resist on the angled portion of the HDP fill.